High quality, high reliability, spirally wound, film capacitors for industrial applications require high quality dielectric films. Film limitations are generally due to poor insulation resistance and/or low dielectric breakdown strengths.
Dielectric breakdown strengths, V.sub.b, of thin polymer films play a key role in determining ultimate attainable energy densities when these films are used as dielectrics in capacitor applications. This is because attainable energy densities of film capacitors increase as the square of the voltage across the capacitor. If V.sub.b of polymer films can be increased these films can be made thinner, or in other words, capacitors can be operated at higher voltages that translate into higher electrostatic energy densities.